Ed. note: Video of the Week picks are supplied by the editors of Common Sense Education, which helps educators find the best ed-tech tools, learn best practices for teaching with tech, and equip ...

Every educator knows what “a teachable moment” is. It’s the brief period of time when events serendipitously conspire to teach students something that otherwise might be difficult for them to learn.

There’s a war of sorts going on within the normally staid assessment industry, and it’s a war over the definition of a type of assessment that many educators understand in only the sketchiest fashion.